About Lung Cancer

Lung Cancer Facts
  • Each year, some 220,000 people in the United States are diagnosed with lung cancer, making it one of the most common types of cancer. More people die of lung cancer than any other type of cancer.
  • Most people who get lung cancer are or were smokers, but the rate of lung cancer is rising among non-smokers, particularly women who’ve never smoked. If you’re a smoker, the best way to reduce your risk of developing lung cancer is to quit smoking -- even if you’ve been smoking for years.
  • Lung cancer forms in lung tissue, usually in the cells lining air passages, when abnormal cells start to grow and reproduce themselves and gather together to form a tumor. The malignant cells destroy the healthy lung tissue around them.
  • Lung cancer can spread by cancerous cells carried through the blood or lymphatic vessels, which carry a clear fluid called lymph away from the lungs. The most common areas to which lung cancer spreads are the lymph nodes, bones, liver, brain and adrenal glands.
Types of Lung Cancer

The two main types of lung cancer – non-small cell and small cell – are classified by their different cell structures when examined under a microscope.

Non-Small Cell Lung Cancer (NSCLC)
Non-small cell lung cancer is the most common type of lung cancer, representing approximately 85 to 90 percent of lung cancers.   Non-small cell lung cancer has three main subtypes:
  • Adenocarcinoma – Adenocarcinoma, which begins in cells that line the alveoli, is the most common type of lung cancer. While this type of lung cancer occurs mainly in current or former smokers, it also is the most common type of lung cancer seen in non-smokers. It is more prevalent in women than in men and is more likely than other types of cancer to occur in younger people
  • Squamous cell (epidermoid) carcinoma – Representing approximately 25 to 30 percent of all lung cancers, squamous cell carcinoma begins in thin, flat cells that line the bronchial tubes in the center of the lungs, near a bronchus. It is most often caused by tobacco smoking.
  • Large cell (undifferentiated) carcinoma –Large cell carcinoma, which can start anywhere in the lungs, is almost always associated with smoking.
  • Other subtypes –Other forms of non-small cell lung cancer are rarer, and include adenosquamous carcinoma, carcinoid (well-differentiated neuroendocrine tumor),  and sarcomatoid carcinoma.

Small Cell Lung Cancer

Also known as oat cell cancer, oat cell carcinoma and small cell undifferentiated carcinoma, this type of lung cancer makes up less than 20% of lung cancers and almost always is caused by tobacco smoking. It tends to grow quickly and spread widely to other parts of the body fairly early in the course of the disease, but often responds well to chemotherapy.
Lung Metastases

Sometimes cancer found in the lungs is not lung cancer at all. It can also be another type of cancer that started elsewhere in the body and spread (metastasized) to the lungs. Lung metastases are identified as the primary, or original, type of cancer.
Each type of lung cancer grows and is treated in different ways. Your City of Hope team of lung cancer experts will carefully study your individual case and work with you to determine the best treatment plan for you. Learn more about our approach to diagnosis and staging.

Risk Factors

Tobacco smoking is by far the most important risk factor for lung cancer, causing 90 percent of cases in men and about 80 percent of cases in women. Cigarette, pipe and cigar smoking all add to the risk of lung cancer. Low tar or nicotine cigarettes do not lower that risk.

Secondhand smoke
People exposed to secondhand tobacco smoke are also at a higher risk of developing lung cancer. People who breathe in the smoke exhaled by smokers are exposed to cancer-causing agents.

Radon exposure
Exposure to radon, a radioactive gas, can increase the risk of lung cancer. Radon, from the breakdown of uranium in rocks, can come up through the ground and leak into buildings. Of nonsmokers killed by lung cancer, about 30 percent had been exposed to radon.

Family history
A person with a family member who has had lung cancer may be at an increased risk of developing the disease.

Other risk factors
Other risk factors for lung cancer include air pollution, and exposure to asbestos, nickel, chromium, arsenic and tar.

Lung cancer symptoms vary from person to person – and early lung cancer sometimes does not cause symptoms. Common symptoms may include:
  • a cough that worsens or does not go away
  • breathing trouble, such as shortness of breath
  • constant chest pain, worsened by deep breathing, coughing or laughing
  • coughing up blood or rust-colored spit
  • persistent hoarseness
  • frequent lung infections, such as pneumonia or bronchitis
  • swelling of the neck and face
  • arm or shoulder pain
  • ongoing fatigue
  • loss of appetite or unexplained weight loss

Having one or more of these symptoms does not necessarily mean you have lung cancer. Nonetheless, early detection and treatment is critical with any illness – especially cancer, so it’s important to see a doctor right away if you experience any of the above symptoms.
For learn more about lung cancer, watch this Ask the Experts video with City of Hope’s lung cancer team members Dan Raz, M.D., and Jae Kim, M.D.